1. Field of the Invention
The invention provides a means for automatically obtaining water samples from precipitation events which are to undergo analysis for trace chemical constituents. The sampler can operate unattended for long periods and collect multiple samples in sealed bottles of inert plastic. The time of sampling and duration of sampling are both recorded.
The importance of the physio-chemical analysis of rain and other forms of precipitation has become increasingly important as concern over atmospheric pollution mounts and techniques for measuring an ever increasing number of contaminants in smaller concentrations continue to be developed. As in all material analysis, the information is only as good as the quality of the collected sample and the information available from it. Consequently, as the information desired becomes more extensive and more affected by a greater number of variables, the sample collection procedure employed must of necessity become more sophisticated.
Collection of rain samples would appear to be a simple matter. However, the analyst is typically looking for constituents present in concentrations of parts per million or even less; hence, the collection equipment must be very clean and all surfaces which come in contact with the sample should be of relatively inert material which will not in itself be of a source of contamination.
The exact time of collection of the sample can be of importance in many studies since results can be related to meteoroligical data. The collection site may frequently be relatively inaccessible and it is often desirable to collect only the early part of an extended precipitation event since most of the contaminants which are scrubbed out of the atmosphere will be present in samples collected during the initial period. Consequently, a sampling device which operates automatically and which is capable of recording the time at which the sample was collected is very nearly essential. Concern over the harmful effects of pollution are resulting in an ever increasing number of legal actions; thus, the importance of a sound sampling system cannot be overstated when results of pollution studies are introduced as evidence in the courts.